Management of Ipsilateral Breast Tumor Recurrence Following Breast Conservation Surgery for Ductal Carcinoma In Situ: A Data-Poor Zone.

BACKGROUND: Breast conserving surgery (BCS) is well established for the management of ductal carcinoma in situ (DCIS), but neither randomized trials nor guidelines address management of ipsilateral breast tumor recurrence (IBTR) after BCS for DCIS. PATIENTS AND METHODS: We identified women treated with BCS for DCIS who developed IBTR as a first event. Between those treated with mastectomy versus re-BCS, we compare the clinicopathologic characteristics, the use of adjuvant radiotherapy (RT) both upfront ("primary RT") and post IBTR ("secondary RT"), of tamoxifen, the rate of third events (local, regional, distant), and both breast cancer specific (BCSS) and overall survival (OS). RESULTS: Of 3001 women treated with BCS for DCIS (1978-2010), 383 developed an IBTR as a first event (1983-2023) and were treated by mastectomy (51%) versus re-BCS (49%). Compared with re-BCS, mastectomy patients at initial treatment were higher grade (74% versus 59%, p = 0.004), with more frequent primary RT (61% versus 21%, p < 0.001). Third local events were more frequent for re-BCS than mastectomy (16% versus 3%, p = 0.001), but there were no differences in breast cancer specific or overall survival. CONCLUSIONS: For isolated IBTR following BCS for DCIS and treated by mastectomy versus re-BCS (1) mastectomy was associated with less favorable initial pathology and more frequent use of primary RT, (2) re- recurrence was more frequent with re-BCS, and (3) BCSS and OS were comparable. Our data suggest a wider role for re-BCS and further study of the relationship between secondary RT and the rate of third breast events.

Changes in the Diagnoses of Breast Core Needle Biopsies on Second Review at a Tertiary Care Center: Implications for Surgical Management.

Core needle biopsy (CNB) of breast lesions is routine for diagnosis and treatment planning. Despite refinement of diagnostic criteria, the diagnosis of breast lesions on CNB can be challenging. At many centers, including ours, confirmation of diagnoses rendered in other laboratories is required before treatment planning. We identified CNBs first diagnosed elsewhere that were reviewed in our department over the course of 1 year because the patients sought care at our center and in which a change in diagnosis had been recorded. The outside and in-house CNB diagnoses were then classified based on Breast WHO Fifth Edition diagnostic categories. The impact of the change in diagnosis was estimated based on the subsequent surgical management. Findings in follow-up surgical excisions (EXCs) were used for validation. In 2018, 4950 outside cases with CNB were reviewed at our center. A total of 403 CNBs diagnoses were discrepant. Of these, 147 had a change in the WHO diagnostic category: 80 (54%) CNBs had a more severe diagnosis and 44 (30%) a less severe diagnosis. In 23 (16%) CNBs, the change of diagnostic category had no impact on management. Intraductal proliferations (n=54), microinvasive carcinoma (n=18), and papillary lesions (n=35) were the most disputed diagnoses. The in-house CNB diagnosis was confirmed in most cases with available excisions. Following CNB reclassification, 22/147 (15%) lesions were not excised. A change affecting the surgical management at our center occurred in 2.5% of all CNBs. Our results support routine review of outside breast CNB as a clinically significant practice before definitive treatment.

Reporting of Surgically Removed Lymph Nodes for Breast Tumors: Recommendations From the International Collaboration on Cancer Reporting.

CONTEXT.­: The International Collaboration on Cancer Reporting (ICCR), supported by major pathology and cancer organizations, aims at the standardization of evidence-based pathology reporting of different types of cancers, with the inclusion of all parameters deemed to be relevant for best patient care and future data collection. Lymph node metastasis is one of the most important prognostic factors in breast cancer. OBJECTIVE.­: To produce a histopathology reporting guide by a panel of recognized experts from the fields of pathology and surgery with elements deemed to be core (required) and noncore (recommended) to report when assessing regional lymph nodes of patients with breast cancer. DATA SOURCES.­: Published literature, previous guidelines/recommendations, and current cancer staging principles were the basis of the data set drafted by the expert panel. This was discussed in a series of teleconferences and email communications. The draft data set was then made available for public consultation through the ICCR Web site. After this consultation and ICCR ratification, the data set was finalized. CONCLUSIONS.­: The ICCR has published a data set for the reporting of surgically removed lymph nodes (including sentinel lymph node biopsy, axillary lymph node dissection, targeted axillary surgery, and lymph node sampling specimens) for breast tumors. This is part of a series of 4 ICCR breast cancer-related data sets. It includes 10 core elements along with 2 noncore elements. This should allow for synoptic reporting, which is more precise, uniform, and complete than nonsynoptic reporting, and leads to improved patient outcomes.

Five decades of progress in surgical oncology: Breast.

Surgery remains the single most effective treatment for breast cancer but coincident with a deeper understanding of tumor biology and advances in multidisciplinary care (encompassing breast imaging, systemic adjuvant therapy, radiotherapy, and genomics) continues to de-escalate, supported by strong level I data. We have moved from mastectomy to breast conservation, and from routine axillary dissection to sentinel lymph node biopsy to selective omission of axillary node staging altogether. We have further de-escalated through consensus over margin width in breast conservation, through improvements in neoadjuvant therapy, and by demonstrating no benefit for upfront surgery in patients with stage IV disease. For patients with ipsilateral breast tumor recurrence, reconservation surgery and reirradiation are promising. Cell cycle and immune checkpoint inhibitors, when added to conventional systemic therapy, have now moved beyond stage IV disease to phase III trials in the adjuvant and neoadjuvant settings, promising even further de-escalation of surgery. Finally, with genomic profiling we are moving away from the primacy of axillary node status for prognostication and into a new era allowing prediction of response to therapy.

Association Between Local Anesthetic Dosing, Postoperative Opioid Requirement, and Pain Scores After Lumpectomy and Sentinel Lymph Node Biopsy with Multimodal Analgesia.

BACKGROUND: Multimodal analgesia (MMA) during breast surgery reduces postoperative pain and opioid requirements, but the relative contribution of local anesthetic dosing as a component of MMA is not well defined among patients undergoing lumpectomy and sentinel lymph node biopsy (SLNB). PATIENTS AND METHODS: We identified consecutive patients who underwent lumpectomy and SLNB with MMA from 1/2019 to 4/2020. Univariable and multivariable linear and logistic regression were used to examine associations between local anesthetics, opioid requirements in the post-anesthesia care unit (PACU), and pain scores in the PACU and on postoperative day (POD) 1. RESULTS: In total, 1603 patients [median tumor size, 14 mm (interquartile range 8-20 mm)] were included. The median PACU opioid requirement was 0 morphine milligram equivalents (interquartile range 0-5). PACU maximum pain was none or mild in 58% of patients and moderate to severe in 42%; among 420 survey respondents, 56% reported no or mild pain and 44% reported moderate to severe pain on POD 1. On multivariable analysis that adjusted for routine components of MMA, increasing doses of 0.5% bupivacaine were associated with reduced PACU opioid requirements (ß -0.04, 95% confidence interval -0.07 to -0.01, p = 0.011) and lower odds of moderate to severe pain (odds ratio 0.98, 95% confidence interval 0.97-0.99, p < 0.001). Local anesthetics were not associated with pain scores on POD 1. CONCLUSIONS: Higher amounts of local anesthetics reduce acute postoperative pain and opioid requirement after lumpectomy and SLNB. Maximizing dosing within weight-based limits is a low-risk, cost-effective pain control strategy that can be used in diverse practice settings.

Nodal Recurrence in Patients With Node-Positive Breast Cancer Treated With Sentinel Node Biopsy Alone After Neoadjuvant Chemotherapy-A Rare Event.

IMPORTANCE: Prospective trials have demonstrated sentinel lymph node (SLN) false-negative rates of less than 10% when 3 or more SLNs are retrieved in patients with clinically node-positive breast cancer rendered clinically node-negative with neoadjuvant chemotherapy (NAC). However, rates of nodal recurrence in such patients treated with SLN biopsy (SLNB) alone are unknown because axillary lymph node dissection (ALND) was performed in all patients, limiting adoption of this approach. OBJECTIVE: To evaluate nodal recurrence rates in a consecutive cohort of patients with clinically node-positive (cN1) breast cancer receiving NAC, followed by a negative SLNB using a standardized technique, and no further axillary surgery. DESIGN, SETTING, AND PARTICIPANTS: From November 2013 to February 2019, a cohort of consecutively identified patients with cT1 to cT3 biopsy-proven N1 breast cancer rendered cN0 by NAC underwent SLNB with dual tracer mapping and omission of ALND if 3 or more SLNs were identified and all were pathologically negative. Metastatic nodes were not routinely clipped, and localization of clipped nodes was not performed. The study was performed in a single tertiary cancer center. INTERVENTION: Omission of ALND in patients with cN1 breast cancer after NAC if 3 or more SLNs were pathologically negative. MAIN OUTCOME AND MEASURES: The primary outcome was the rate of nodal recurrence among patients with cN1 breast cancer treated with SLNB alone after NAC. RESULTS: Of 610 patients with cN1 breast cancer treated with NAC, 555 (91%) converted to cN0 and underwent SLNB; 234 (42%) had 3 or more negative SLNs and had SLNB alone. The median (IQR) age of these 234 patients was 49 (40-58) years; median tumor size was 3 cm; 144 (62%) were ERBB2 (formerly HER2)-positive, and 43 (18%) were triple negative. Most (212 [91%]) received doxorubicin-based NAC; 205 (88%) received adjuvant radiotherapy (RT), and 164 (70%) also received nodal RT. At a median follow-up of 40 months, there was 1 axillary nodal recurrence synchronous with local recurrence in a patient who refused RT. Among patients who received RT (n = 205), there were no nodal recurrences. CONCLUSIONS AND RELEVANCE: This cohort study found that in patients with cN1 disease rendered cN0 with NAC, with 3 or more negative SLNs with SLNB alone, nodal recurrence rates were low, without routine nodal clipping. These findings potentially support omitting ALND in such patients.

Postdischarge Nonsteroidal Anti-Inflammatory Drugs Are not Associated with Risk of Hematoma after Lumpectomy and Sentinel Lymph Node Biopsy with Multimodal Analgesia.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) are increasingly used in ambulatory breast surgery. The risk of hematoma associated with intraoperative ketorolac is low, but whether concomitant routine discharge with NSAIDs increases the risk of hematoma is unclear. METHODS: We retrospectively identified patients who underwent lumpectomy and sentinel lymph node biopsy (SLNB), and compared the 30-day risk of hematoma between patients discharged with opioids (opioid period: January 2018-August 2018) and patients discharged with NSAIDs with or without opioids (NSAID period: January 2019-April 2020). The association between study period and hematoma risk was assessed using multivariable models. Covariates included intraoperative ketorolac, home aspirin, and race/ethnicity. During the NSAID period, a survey was used to assess analgesic consumption on postoperative days 1-5. RESULTS: In total, 2724 patients were identified: 858 (31%) in the opioid period and 1866 (69%) in the NSAID period. In the NSAID period, 867 (46%) received NSAIDs and opioids, and 999 (54%) received NSAIDs only. Receipt of intraoperative ketorolac was higher in the NSAID period (78 vs. 64%, P < 0.001). The risks of any hematoma (4.1 vs. 3.6%, P = 0.6) and reoperation for bleeding (0.5 vs. 0.6%, P = 0.8) were similar between groups. Study period was not associated with hematoma risk (odds ratio 0.87, 95% confidence interval 0.56-1.35, P = 0.5). Among survey respondents (41%), nonopioid analgesic consumption did not increase after opioids were removed from the discharge regimen (median, 6 pills/group, P = 0.06). CONCLUSIONS: NSAIDs are associated with a low risk of hematoma after lumpectomy and SLNB, and should be prescribed instead of opioids, unless contraindicated.

Salvage of locally recurrent breast cancer with repeat breast conservation using 45 Gy hyperfractionated partial breast re-irradiation.

PURPOSE: Mastectomy has long been the preferred approach for local salvage of recurrent breast cancer following breast-conservation therapy (BCT). Growing interest in avoiding mastectomy prompted RTOG 1014, a landmark phase two study demonstrating the feasibility of repeat BCT using a novel radiotherapy (RT) regimen (i.e., 45 Gy administered in 30 fractions of 1.5 Gy twice-daily to the partial breast, "rePBI"). We adopted this regimen as our institutional standard and report our observations regarding the safety and efficacy of rePBI as salvage therapy. METHODS: All patients at our institution who underwent repeat BCT and subsequently received rePBI from 2011 to 2019 were identified. Clinicopathologic features and treatment characteristics for both primary breast cancers and recurrences were collected, as were rates of subsequent recurrence and treatment-associated toxicities. RESULTS: The cohort included 34 patients with a median age of 65.8 (46.2-78.2) at the time of rePBI. At a median follow-up of 23.5 months, there were two subsequent locoregional recurrences (2-year local control rate 97%). There was no grade ≥ 3 toxicity. The most common acute toxicity (< 3 months) was radiation dermatitis (100%), and common grade 1-2 late toxicities (> 3 months) included fibrosis in 14 (41%), breast asymmetry in 12 (35%), and chest wall pain in 11 (32%). CONCLUSIONS: Repeat breast conservation using the hyperfractionated partial breast RT regimen defined by RTOG 1014 (45 Gy administered in 30 1.5 Gy twice-daily fractions) appears effective and well tolerated. No grade 3 or higher toxicities were observed and local control was excellent. Longer term follow-up among larger cohorts will define whether salvage mastectomy should remain the preferred standard.

Management of ipsilateral breast tumor recurrence following breast conservation surgery: a comparative study of re-conservation vs mastectomy.

BACKGROUND: Breast conservation therapy (BCT) is well established for the management of primary operable breast cancer, with oncologic outcomes comparable to those of mastectomy. It remains unclear whether re-conservation therapy (RCT) is suitable for those patients who develop ipsilateral breast tumor recurrence (IBTR), for whom mastectomy is generally recommended. METHODS: We identified women who underwent BCT for invasive or ductal carcinoma in situ and developed IBTR as a first event, comparing the pattern of subsequent events and survival for those treated by RCT versus mastectomy. RESULTS: Of 16,968 patents who had BCT, 322 (1.9%) developed an isolated IBTR as a first event between 1999 and 2019. 130 (40%) had RCT and 192 (60%) mastectomy. Compared to mastectomy, the RCT patients were older (66 vs 53, < 0.001), had a longer disease-free interval (DFI: 5.8 vs 2.7 years (p < 0.001)), were less likely to have received RT (p < 0.001), endocrine therapy (ET) (p < 0.005) or combined RT/ET (< 0.001) as initial treatment, but the characteristics of their initial primary cancers and of their IBTR were comparable. At a median follow-up of 10.7 years following initial BCT and 6.5 years following IBTR, there were no differences in BCSS or OS between RCT and mastectomy. CONCLUSION: For BCT patients who developed IBTR as a first event, we observed comparable BCSS and OS from time of initial treatment and from time of IBTR, whether treated by RCT or mastectomy. These results support wider consideration of RCT in the management of IBTR, especially in the setting of older age and longer DFI.

Microscopic Extracapsular Extension in Sentinel Lymph Nodes Does Not Mandate Axillary Dissection in Z0011-Eligible Patients.

BACKGROUND: In the ACOSOG (American College of Surgeons Oncology Group) Z0011 trial and the AMAROS (After Mapping of the Axilla: Radiotherapy or Surgery?) trial, matted nodes with gross extracapsular extension (ECE), a risk factor for locoregional recurrence, were an indication for axillary lymph node dissection (ALND), but the effect of microscopic ECE (mECE) in the sentinel lymph nodes (SLNs) on recurrence was not examined. METHODS: Between 2010 and 2017, 811 patients with cT1-2N0 breast cancer and SLN metastasis were prospectively managed according to Z0011 criteria, with ALND for those with more than two positive SLNs or gross ECE. Management of mECE was not specified. In this study, we compare outcomes of patients with one to two positive SLNs with and without mECE, treated with SLN biopsy alone (n = 685). RESULTS: Median patient age was 58 years, and median tumor size was 1.7 cm. mECE was identified in 210 (31%) patients. Patients with mECE were older, had larger tumors, and were more likely to be hormone receptor positive and HER2 negative, have two positive SLNs, and receive nodal radiation. At a median follow-up of 41 months, no isolated axillary failures were observed. There were 11 nodal recurrences; two supraclavicular ± axillary, four synchronous with breast, and five with distant failure. The five-year rate of any nodal recurrence was 1.6% and did not differ by mECE (2.3% vs. 1.3%; p = 0.84). No differences were observed in local (p = 0.08) or distant (p = 0.31) recurrence rates by mECE status. CONCLUSIONS: In Z0011-eligible patients, nodal recurrence rates in patients with mECE are low after treatment with SLN biopsy alone, even in the absence of routine nodal radiation. The presence of mECE should not be considered a routine indication for ALND.

Correction to: Factors Associated with Reoperation in Breast-Conserving Surgery for Cancer: A Prospective Study of American Society of Breast Surgeon Members.

The Disclosures in the original article are incomplete. Not included is the following information.

Factors Associated with Reoperation in Breast-Conserving Surgery for Cancer: A Prospective Study of American Society of Breast Surgeon Members.

BACKGROUND: More than 20% of patients undergoing initial breast-conserving surgery (BCS) for cancer require reoperation. To address this concern, the American Society of Breast Surgeons (ASBrS) endorsed 10 processes of care (tools) in 2015 to be considered by surgeons to de-escalate reoperations. In a planned follow-up, we sought to determine which tools were associated with fewer reoperations. METHODS: A cohort of ASBrS member surgeons prospectively entered data into the ASBrS Mastery® registry on consecutive patients undergoing BCS in 2017. The association between tools and reoperations was estimated via multivariate and hierarchical ranking analyses. RESULTS: Seventy-one surgeons reported reoperations in 486 (12.3%) of 3954 cases (mean 12.7% [standard deviation (SD) 7.7%], median 11.5% [range 0-32%]). There was an eightfold difference between surgeons in the 10th and 90th percentile performance groups. Actionable factors associated with fewer reoperations included routine planned cavity side-wall shaves, surgeon use of ultrasound (US), neoadjuvant chemotherapy, intra-operative pathologic margin assessment, and use of a pre-operative diagnostic imaging modality beyond conventional 2D mammography. For patients with invasive cancer, ≥ 24% of those who underwent reexcision did so for reported margins of < 1 or 2 mm, representing noncompliance with the SSO-ASTRO margin guideline. CONCLUSIONS: Although ASBrS member surgeons had some of the lowest rates of reoperation reported in any registry, significant intersurgeon variability persisted. Further efforts to lower rates are therefore warranted. Opportunities to do so were identified by adopting those processes of care, including improved compliance with the SSO-ASTRO margin guideline, which were associated with fewer reoperations.

Comparison of Local Recurrence Risk Estimates After Breast-Conserving Surgery for DCIS: DCIS Nomogram Versus Refined Oncotype DX Breast DCIS Score.

BACKGROUND: A ductal carcinoma in situ (DCIS) Nomogram integrating 10 clinicopathologic/treatment factors and a Refined DCIS Score (RDS) that incorporates a genomic assay and three clinicopathologic factors (Oncotype DX DCIS Score) are available to estimate DCIS 10-year local recurrence risk (LRR). This study compared these estimates. METHODS: Patients 50 years of age or older with DCIS size 2.5 cm or smaller and a genomic assay available were identified. An RDS within 1-2% of the range of Nomogram LRR estimates obtained by assuming use and non-use of endocrine therapy (Nomogram ± ET) was defined as concordant. Assuming a 10-year risk threshold of 10% for recommending radiation, Nomogram ± ET and RDS estimates were compared, and threshold concordance was determined. RESULTS: For 54 (92%) of 59 patients, the RDS and Nomogram ± ET LRR estimates were concordant. For the remaining 5 (8%) of the 59 patients, the RDS LRR estimates were lower than the Nomogram + ET estimates, with an absolute difference of 3-8%, and thus were discordant. For these five patients, the RDS estimates of 10-year LRR were lower than 10% (range 5-8%) and the Nomogram + ET estimates were 10% or higher (range 11-14%). These five patients with both discordant and threshold-discordant estimates all had close margins (≤ 2 mm). CONCLUSIONS: Among 92% of women 50 years of age or older with DCIS size 2.5 cm or smaller, free-of-charge online Nomogram 10-year LRR estimates were concordant with those obtained using the commercially available RDS (> $4600). Among the 8% with discordant risk estimates, the RDS appeared to underestimate the LRR and may lead to inappropriate omission of radiotherapy. Unless other data show a clinically significant advantage of the RDS (Oncotype DX DCIS Score), the study data suggest that for women 50 years of age or older with DCIS size 2.5 cm or smaller, its use is not warranted.

Is Sentinel Lymph Node Biopsy Required for a Core Biopsy Diagnosis of Ductal Carcinoma In Situ with Microinvasion?

BACKGROUND: Among patients with a core biopsy diagnosis of ductal carcinoma in situ (DCIS), approximately 10% have microinvasion (DCISM), which, like DCIS, is subject to upstaging by surgical excision, but for which the rates of T and N upstaging are unknown, as is the role of sentinel lymph node biopsy (SLNB), since current studies of SLNB for DCISM are based on the final pathologic report, not the core needle biopsy. In this study, we identified the rates of T and N upstaging following surgical excision in patients with a suspected versus definite core needle biopsy diagnosis of DCISM. METHODS: Overall, 369 consecutive patients (2007-2017) with a core biopsy diagnosis of suspected versus definite DCISM and surgical excision were stratified by extent of DCISM on core biopsy: suspicious focus, single focus, multiple foci/single biopsy, and multiple foci/multiple biopsies. Within strata, we identified clinicopathologic features associated with T and N upstaging. RESULTS: Across core biopsy strata, there were no clear differences in imaging characteristics or median invasive tumor size (0.2 cm). Among 105 patients with a core biopsy suspicious for DCISM versus 264 with definite DCISM, 28% and 37%, respectively, were upstaged to at least pT1a, but only 1% and 6%, respectively, to pN1. CONCLUSIONS: Although 28% of patients with suspected DCISM on core biopsy were surgically upstaged to invasive cancer, the frequency of pN1 SLN metastasis (1%) was comparable with that of DCIS, and was insufficient to recommend SLNB at initial surgery. SLNB remains reasonable for patients with definite DCISM on core biopsy.

Does every woman presenting with malignant calcifications require a post lumpectomy mammogram?

PURPOSE: Successful breast-conserving surgery (BCS) followed by radiation therapy (XRT) is dependent on complete removal of the cancer with clear surgical margins, providing survival rates equivalent to those observed following mastectomy. In patients who have cancers presenting with microcalcifications, post lumpectomy mammograms (PLM) prior to radiation (XRT) can be performed to ensure that no cancer has been left behind. The purpose of this study was to assess the benefit of PLM in patients with malignant breast tumors presenting with microcalcifications. METHODS: In this IRB-approved retrospective study, we reviewed medical records for patients with breast cancers presenting with microcalcifications who underwent BCS between February 2008 and June 2013. 198 patients who had a PLM prior to XRT for cancers presenting with microcalcifications were included. RESULTS: Histopathology of the initial lumpectomy revealed invasive carcinoma in 78/198 (39.4%) and DCIS alone in 120/198 (60.6%). 114/198 (58%) patients had negative surgical margins. 7/114 (6%) patients with negative margins had positive PLM and re-excisions that were positive for malignancy: sensitivity 88%, specificity 95%, PPV 58%, NPV 99%. 84/198 patients had positive surgical margins. The diagnostic performance of PLM in this group was: sensitivity 55%, specificity 71%, PPV 66%, NPV 61%. CONCLUSION: PLM plays an important role in the evaluation of patients undergoing breast conservation for breast cancer presenting with microcalcifications. Residual malignancy was detected on positive PLM in 6% of patients with negative margins.

Impact of an In Situ Component on Outcome After In-Breast Tumor Recurrence in Patients Treated with Breast-Conserving Therapy.

BACKGROUND: Among all in-breast tumor recurrences (IBTR) following breast-conserving therapy (BCT), some comprise metachronous new primaries (NPs) while others are true recurrences (TRs). Establishing this distinction remains a challenge. METHODS: We studied 3932 women who underwent BCT for stage I-III breast cancer from 1998 to 2008. Of these, 115 (2.9%) had an IBTR. Excluding patients with inoperable/unresectable recurrences or simultaneous distant metastases, 81 patients with isolated IBTR comprised the study population. An IBTR was categorized as an NP rather than a TR if it included an in situ component. The log-rank test and Kaplan-Meier method were used to evaluate disease-free survival (DFS) and overall survival (OS), and univariate and multivariate analyses were performed using Cox proportional hazards regression models. RESULTS: At a median of 64.5 months from IBTR diagnosis, 28 of 81 patients had DFS events. Five-year DFS was 43.1% in the TR group (p = 0.0001) versus 80.3% in the NP group, while 5-year OS was 59.7% in the TR group versus 91.7% among those with NPs (p = 0.0011). On univariate analysis, increasing tumor size, high grade, positive margins, lymphovascular invasion, node involvement, lack of axillary surgery, chemotherapy, radiation therapy, and IBTR type (TR vs. NP) were significantly associated with worse DFS. Controlling for tumor size and margin status, TRs remained significantly associated with lower DFS (hazard ratio 3.717, 95% confidence interval 1.607-8.595, p = 0.002). CONCLUSION: The presence of an in situ component is associated with prognosis among patients with IBTR following BCT and may be useful in differentiating TRs and NPs.

Axillary Dissection and Nodal Irradiation Can Be Avoided for Most Node-positive Z0011-eligible Breast Cancers: A Prospective Validation Study of 793 Patients.

OBJECTIVE: To determine rates of axillary dissection (ALND) and nodal recurrence in patients eligible for ACOSOG Z0011. BACKGROUND: Z0011 demonstrated that patients with cT1-2N0 breast cancers and 1 to 2 involved sentinel lymph nodes (SLNs) having breast-conserving therapy had no difference in locoregional recurrence or survival after SLN biopsy alone or ALND. The generalizability of the results and importance of nodal radiotherapy (RT) is unclear. METHODS: Patients eligible for Z0011 had SLN biopsy alone. Prospectively defined indications for ALND were metastases in ≥3 SLNs or gross extracapsular extension. Axillary imaging was not routine. SLN and ALND groups and radiation fields were compared with chi-square and t tests. Cumulative incidence of recurrences was estimated with competing risk analysis. RESULTS: From August 2010 to December 2016, 793 patients met Z0011 eligibility criteria and had SLN metastases. Among them, 130 (16%) had ALND; ALND did not vary based on age, estrogen receptor, progesterone receptor, or HER2 status. Five-year event-free survival after SLN alone was 93% with no isolated axillary recurrences. Cumulative 5-year rates of breast + nodal and nodal + distant recurrence were each 0.7%. In 484 SLN-only patients with known RT fields (103 prone, 280 supine tangent, 101 breast + nodes) and follow-up ≥12 months, the 5-year cumulative nodal recurrence rate was 1% and did not differ significantly by RT fields. CONCLUSIONS: We confirm that even without preoperative axillary imaging or routine use of nodal RT, ALND can be avoided in a large majority of Z0011-eligible patients with excellent regional control. This approach has the potential to spare substantial numbers of women the morbidity of ALND.